Well they already didn't like the idea of changing nameplates because of stress on the servers, this is even less likely. The game would need to check every character in an area when you open the map, and cross reference it with a potential 512 members in your fc. Imagine the processing of every person in mor dhona checking their map.

In the past we commented that it would be difficult to implement settings that would allow you to change nameplate colors for certain players, but the status has changed slightly and below is a message from Hiroshi Minagawa with an update.

Originally Posted by Hiroshi_Minagawa

Previously I made a comment in response to a request to make it possible to change the nameplate color settings of LS members, FC members, and friends, and I mentioned that it would be difficult to do.

Considering the concerns for worst case scenario when it comes to FC and LS members, there is no change to the fact that we will have to decide on how to handle this extremely carefully.

However, we’ve confirmed that there are no issues when it comes to changing the color of the nameplate for players on your friend list and I’m happy to say that we will be aiming to implement this feature in patch 2.28. We’re currently in the midst of performing our final checks, so hang in there a bit until it’s implemented!

The party leader gets a different icon beside their nameplate. I don't think there has to be anything more than that. Plus chatbox colors are based on chat channel and have nothing to do with character nameplates. Those aren't going to change. This thread and the dev response are for the names above people's heads. With that in mind, take into account that Minigawa stated FC/LS Members getting nameplate colors was difficult. Subdividing FC for Officers/Members would be even harder. Frankly if you have trouble remembering who your officers are you have too many officers.